JPH08320931A - Method and device for inspecting character - Google Patents

Abstract

PURPOSE: To automatically execute inspection approximate to human decision by finding out the matching degree of each pixel value based upon the weight of each area in a divided matrix-like character and comparing the matching degree with a prescribed reference value to judge the quality of the character. CONSTITUTION: A picture processing operation part 1 divides a character in each character sort to be added to an electronic parts 6 into a matrix consisting of the prescribed number of areas and applies weight for checking the existence of a character to each area. Then a display character on the electronic parts 6 is photographed by a video camera 4 as a picture constituted of plural pixels, the range of the displayed character is detected from the photographed picture, the character in the range is segmented and the segmented character is divided like a matrix. After finding out the matching degree of each picture element value based upon the weight of each area of the matrix, the matching degree is compared with a prescribed reference value to judge the quality of the character.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a character inspection method and apparatus for automatically inspecting good products and defective products by character inspection such as marking of electronic parts such as chip resistors.

[0002]

2. Description of the Related Art Conventionally, in the automatic inspection of characters loaded on electronic parts, a video camera images a displayed character of the electronic part, and the area and the center of gravity of each character are measured based on the image obtained by this imaging. Then, the presence / absence of a character, misalignment, and partial omission are determined, and the type of character is determined based on the feature amount of each character.

[0003]

However, in the case of a character loaded on an electronic component, it is within the range of a non-defective item as long as it can be discriminated by a human even if there are some defects. It was difficult to make an ambiguous judgment that humans can distinguish it. In addition, even if it is possible to determine a product that is slightly different from the non-defective sample as a defective product, it is a defect that can be discriminated by humans, and even within the range of a non-defective product, it is often determined as a defective product. It was Further, when trying to determine a defective product that can be discriminated by humans as a non-defective product, there is a problem that a defective product may be erroneously determined as a non-defective product depending on the type of character.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a character inspection method and apparatus capable of automatically performing an inspection close to human judgment.

[0005]

In order to achieve the above object, the present invention provides a character inspection method for inspecting the quality of characters added to the surface of an electronic component according to claim 1, wherein the electronic component is For each character type to be added, the character is divided into a matrix of a predetermined number of areas, and the presence or absence of the character is weighted for each of the divided areas, and an image composed of a plurality of pixels is created. Capturing a display character of the electronic component, detecting the range of the display character from the image, cutting out for each character, dividing the cut out character into a matrix consisting of the predetermined number of regions,
A character inspection method is proposed in which the degree of coincidence regarding the value of each pixel is obtained based on the weighting for each area of the matrix, and whether the character is good or bad is determined by comparing the degree of coincidence with a predetermined reference value.

According to a second aspect of the present invention, in the character inspection method according to the first aspect, the value of the pixel is binarized based on the presence or absence of a character, and when the value and the weighting match, the value of the degree of coincidence is obtained. We propose a character inspection method for counting.

According to a third aspect of the present invention, in the character inspection method according to the first or second aspect, the weighting may include a character, a character does not exist, or a character may or may not exist. We propose a character inspection method that does not count the degree of coincidence in an area in which three types are set and weighted such that the character may or may not exist.

According to a fourth aspect of the present invention, in the character inspection device, the character added to the surface of the electronic component is imaged as an image composed of a plurality of pixels, and the quality of the character is judged based on the image. Weighting storage means that divides the character into a matrix of a predetermined number of areas for each character type to be added to the electronic component, and stores the weighting regarding the presence or absence of the character set for each of the divided areas, Character range detection means for detecting the range of the displayed characters from the image, character cutout means for cutting out each character from the detected character range, and division for dividing the cutout characters into a matrix consisting of the predetermined number of areas Means for calculating the degree of coincidence with respect to the value of each pixel based on the weighting for each area stored in the weighting storage means, Suggest a character inspection apparatus provided with a determination means for determining acceptability of a character by comparing with a predetermined reference value.

According to a fifth aspect of the present invention, in the character inspection apparatus according to the fourth aspect, the arithmetic means binarizes the pixel value based on the presence or absence of a character, and when the value and the weighting match. A character inspection device for counting the value of the degree of coincidence is proposed.

According to a sixth aspect of the present invention, in the character inspection apparatus according to the fourth or fifth aspect, as the weighting in the weighting storage means, characters are present, characters are not present, and characters are present even if they are present. In the area in which the three types, which do not need to be set, are set, and the weighting is performed so that the character may or may not exist, the calculation means does not count the degree of coincidence. Suggest a device.

According to a seventh aspect of the present invention, in the character inspection apparatus according to the fourth, fifth or sixth aspect, an illuminating device for illuminating a character area of the electronic component is provided, and the illuminating device is a ring-shaped first device. We propose a character inspection device consisting of an illuminator and two parallel linear second illuminators.

[0012]

According to claim 1 of the present invention, for each character type to be added to the electronic component, the character is divided into a matrix of a predetermined number of areas, and the presence of the character in each of the divided areas is determined. Weighting regarding presence / absence is performed. After such a setting, a display character of the electronic component is captured as an image composed of a plurality of pixels, a range of the display character is detected from the image, and each character within the range is cut out, The cut out characters are divided into a matrix of the predetermined number of areas. Then, after the degree of coincidence regarding the value of each pixel is obtained based on the weighting for each area of the matrix, the degree of coincidence is compared with a predetermined reference value to judge the quality of the character.

For example, a plurality of basic patterns are prepared for each character type, the basic patterns are compared with the characters to be inspected, and the characters are inspected at the rate of coincidence. Here, by weighting the constituent dots (pixels) in each matrix divided into m × n of the basic pattern, even if the pixel of the part is missing when the character to be inspected is compared with the basic pattern, it is applicable. Whether or not the character can be discriminated can be determined by the weighting value. Therefore, it is not determined whether all the m × n matrixes of the basic pattern of the character and the character to be inspected match, but the important parts (pixels) for determining the character to be inspected as the relevant character. It is possible to perform a strict inspection. Therefore, it is possible to perform an inspection close to the human judgment that the character is within the range of non-defective products if it can be distinguished as the corresponding character.

According to a second aspect, the value of the pixel is binarized based on the presence / absence of a character. For example, a pixel forming a character is binarized as "1", and a pixel not forming a character is binarized as "0". When the binarized value and the weighting match, the value of the matching degree is counted. For example, when a pixel having a value of "1" is detected in a weighted area when a character exists, the matching value is counted up by "1", and when a character does not exist in a weighted area. When a pixel having a value of "0" is detected, the value of the matching degree is incremented by "1". Accordingly, even when a character is deformed due to a missing part of the character, ink bleeding, or the like, it is possible to make a determination close to human visual inspection.

According to a third aspect of the present invention, as the weighting, three types are set, that is, a character exists, a character does not exist, and a character may or may not exist, and the character exists. However, the degree of coincidence is not counted in the area weighted so that it does not have to exist.

According to a fourth aspect of the present invention, by the weighting storage means, for each character type to be added to an electronic component, the character is divided into a matrix of a predetermined number of areas, and the character set for each area is set. The weighting regarding the presence or absence is stored. Further, the character range detecting means detects the range of the display character from the image, and the character cutting means cuts out each character from the detected character range. The cut-out character is divided by the dividing means into a matrix of the predetermined number of areas, and the arithmetic means relates to the value of each pixel based on the weighting for each area stored in the weighting storage means. The degree of coincidence is required. Further, the determining means compares the degree of coincidence with a predetermined reference value to determine the quality of the character.

According to a fifth aspect of the present invention, the value of the pixel is binarized by the calculating means based on the presence or absence of a character, and when the value and the weighting match, the value of the degree of coincidence is counted. To be done.

According to a sixth aspect of the present invention, three types of weights are set in the weighting storage means, that is, a character exists, a character does not exist, and a character may or may not exist. In the area weighted such that the character may or may not exist, the calculation unit does not count the degree of coincidence.

According to a seventh aspect of the invention, there is provided a lighting device comprising a ring-shaped first illuminator and two parallel linear second illuminators for illuminating a character area of the electronic component. For example, the first illuminator is used when detecting the display character range, and the second illuminator is used when cutting out the character.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a character inspection device according to an embodiment of the present invention. In the figure, 1 is an image processing arithmetic unit, 2
Is an image memory, 3 is a display device, 4 is a video camera, 5 is a lighting device, and 6 is an electronic component to be inspected.

The image processing / calculation unit 1 illuminates the electronic component 6 by the illuminating device 5 and captures a character such as a resistance value imprinted on the electronic component 6 by the video camera 4 and forms an image of the obtained image. Stored in the memory 2. After that, based on the image stored in the image memory 2, it is determined by a process described later whether or not the stamp character matches the character stored in advance, and the result is displayed on the display device 3.

As shown in FIG. 2, the illuminating device 5 has a substantially cylindrical frame 5a, and inside thereof is arranged in a ring shape around a camera mounting hole 5b formed at the center. A plurality of light emitting diodes (LEDs) 5c and light emitting diodes (LEDs) 5d linearly arranged on both sides outside the light emitting diodes (LEDs) 5c in a predetermined direction are provided. These light emitting diodes (LED) 5c
The light emitting diode (LED) 5d is selectively used depending on the process of recognizing the character added to the electronic component 6.

As shown in FIG. 3, the electronic component 6 has a substantially rectangular parallelepiped shape, terminal electrodes 6a are formed at both ends in the longitudinal direction thereof, and a three-digit number indicating a resistance value is stamped on the central portion of the upper surface. Has been done.

Next, the processing operation of the character inspection in this embodiment having the above-mentioned structure will be described with reference to the flow chart shown in FIG. When the electronic component 6 is placed at a predetermined position, the image processing calculation unit 1 illuminates the electronic component with the light emitting diode (LED) 5c of the lighting device 5 (SA1).
At the same time, the video camera 4 captures a still image of the electronic component 6 (SA2).

As a result, as shown in FIG. 5, it is possible to obtain an image in which a rough portion (character range) CE in which a character is located is raised, and the character range CE is detected (SA3).
be able to.

After that, the image processing operation unit 1 is operated by the illumination device 5
The electronic component 6 is illuminated by the light emitting diode (LED) 5d (SA4), and a still image of the electronic component 6 is captured by the video camera 4 (SA5).

As a result, it is possible to obtain an image in which characters are highlighted as shown in FIG. 6, and it is possible to detect the character position.

Next, the obtained image data is binarized (SA6) and each character position is detected (SA7).

Next, each character is cut out (SA8), and each of the cut out characters is arranged in the horizontal direction 4 and the vertical direction 5 as shown in FIG.
Is divided into a matrix (SA9). In each of the divided areas ER, for example, as shown in FIG.
The pixel P of 0 is included. Regarding the digital values of these pixels, the pixels that form a character have a value of "1", and the pixels that do not form a character have a value of "0".

Here, each area divided into a matrix is weighted for each character type. For example,
In the character "3" shown in FIG. 7, as shown in FIG. 9, "2", "1", "1", "2", "0" are sequentially displayed from the area of "A-1" to the area of "E-4". "0""2""1"
"0""2""1""1""0""0""2""1"
Weighting of “2”, “1”, “1”, and “1” is performed.
This weighting “0” means that there are no pixels that form a character, “1” means that there are pixels that form a character, and “2” indicates that there are pixels that form a character. Means that it does not have to exist.

Further, a plurality of types of weighting are set for each character. For example, for the character "3", in addition to the weighting shown in FIG. 9, three types of weighting shown in FIG. 10 are set.

The image processing calculation unit 1 counts the degree of coincidence of the cut-out characters using a plurality of preset weighting patterns (SA10), and the weighting pattern having the degree of coincidence equal to or higher than a predetermined reference value. The character to be inspected is recognized as a "good" character and is recognized as "good".

Counting the degree of coincidence is performed as follows. That is, when there is a pixel having a value of "1" in the area of weight "1", the degree of coincidence is increased by "1", and a pixel having a value of "0" appears in the area of weight "0". When it exists, the degree of coincidence is increased by "1". Further, regarding the area of the weighting “2”, as described above, the pixels forming a character may or may not exist, and therefore do not contribute to the counting of the degree of coincidence.

As a result, in units of pixels forming a character,
Since the quality of the character can be determined, the character to be inspected is determined to be the corresponding character, not to determine whether the basic pattern of the character and all the m × n matrices in the character to be inspected match. It is possible to strictly inspect an important portion (pixel), and it is possible to perform an inspection close to a human determination that if it can be discriminated as a corresponding character, it falls within the range of non-defective products.

Further, since the area of weighting "2" is provided, even when a character is deformed due to a part of the character being missing, ink bleeding, etc., it is possible to make a judgment similar to human visual inspection.

As described above, the quality of the character is judged by weighting (SA11), and when all the characters added to the electronic component 6 are judged to be "good", the comprehensive judgment is judged to be "good". It The determination result is displayed on the display device 3 (SA12).

The number of divisions of the matrix and the setting values of weighting are not limited to those of this embodiment.

[0038]

As described above, according to the character inspection method of the first aspect of the present invention, by weighting each area in the matrix divided into a plurality of areas, the character to be inspected is a basic pattern. When comparing with, it is possible to determine whether or not it is possible to determine as a corresponding character even if pixels of any part are missing, so it is possible to determine the character to be inspected as a corresponding character. Therefore, it becomes possible to strictly inspect an important portion (pixel) for performing the inspection, and an inspection close to human judgment can be automatically performed.

According to the character inspection method of the second aspect, in addition to the above effect, the value of the pixel is binarized based on the presence or absence of a character, and when the value and the weighting match, the character value is binarized. Since the value of the degree of coincidence is counted, even if characters are partially deformed or the characters are deformed due to ink bleeding, etc.
It is possible to make a judgment similar to that of human eyes.

According to the character inspection method of the third aspect, in addition to the above effects, as the weighting, there is a character, a character does not exist, and a character exists or does not exist. In the area in which three types of good are set and the weight is determined such that the character may or may not exist, the degree of coincidence is not counted, so that there is some ambiguity in the inspection determination. Can be made.

According to the character inspection apparatus of the fourth aspect, by weighting each area in the matrix divided into a plurality of areas, when comparing the character to be inspected with the basic pattern, Since it is possible to determine whether or not it is possible to determine the corresponding character even if the pixel of the part is missing, it is important to determine the character to be inspected as the corresponding character (pixel )
With respect to, it becomes possible to perform a strict inspection, and an inspection close to human judgment can be automatically performed.

Further, according to the character inspection apparatus of the fifth aspect, in addition to the above effect, the value of the pixel is binarized based on the presence or absence of a character, and when the value and the weighting match, the character value is binarized. Since the value of the degree of coincidence is counted, even if characters are partially deformed or the characters are deformed due to ink bleeding, etc.
It is possible to make a judgment similar to that of human eyes.

According to the character inspection apparatus of the sixth aspect, in addition to the above effects, as the weighting, there is a character, there is no character, and whether there is a character or not. In the area in which three types of good are set and the weight is determined such that the character may or may not exist, the degree of coincidence is not counted, so that there is some ambiguity in the inspection determination. Can be made.

Further, according to the character inspection apparatus of the seventh aspect, an illuminator used for detecting the display character range and an illuminator suitable for cutting out characters are used. It is possible to accurately detect characters.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a lighting device according to an embodiment of the present invention.

FIG. 3 is a diagram showing an electronic component to be inspected in one embodiment of the present invention.

FIG. 4 is a flowchart illustrating an inspection method according to an embodiment of the present invention.

FIG. 5 is a diagram illustrating a character area detection method according to an embodiment of the present invention.

FIG. 6 is a diagram illustrating a character detection method according to an embodiment of the present invention.

FIG. 7 is a diagram illustrating matrix division according to an embodiment of the present invention.

FIG. 8 is a diagram for explaining character constituent pixels according to an embodiment of the present invention.

FIG. 9 is a diagram illustrating weighting according to an embodiment of the present invention.

FIG. 10 is a diagram illustrating an example of weighting according to an embodiment of the present invention.

[Explanation of symbols]

1 ... Image processing operation unit, 2 ... Image memory, 3 ... Display device, 4
... video camera, 5 ... illumination device, 5a ... frame, 5b ... camera mounting hole, 5c, 5d ... light emitting diode (LED),
6 ... Electronic component, 6a ... Terminal electrode, CE ... Character range, ER
... area, P ... pixel.

Claims (7)

[Claims] 1. A character inspection method for inspecting the quality of a character added to the surface of an electronic component, wherein the character is divided into a matrix of a predetermined number of regions for each character type to be added to the electronic component. , The presence or absence of a character is weighted for each of the divided regions, the display character of the electronic component is imaged as an image composed of a plurality of pixels, and the range of the display character is detected from the image. At the same time, each character is cut out, the cut out character is divided into a matrix consisting of the predetermined number of areas, and the degree of coincidence regarding the value of each pixel is calculated based on the weighting for each area of the matrix, A character inspection method characterized by determining the quality of a character by comparing the degree of coincidence with a predetermined reference value. 2. The character inspection according to claim 1, wherein the value of the pixel is binarized based on the presence or absence of a character, and the value of the degree of coincidence is counted when the value and the weighting match. Method. 3. A character exists as the weighting,
In the area in which three types are set, that is, the character does not exist and the character may or may not exist, and the weight is determined such that the character may or may not exist, The character inspection method according to claim 1 or 2, wherein the counting is not performed. 4. A character inspection device for picking up a character added to the surface of an electronic component as an image composed of a plurality of pixels, and determining whether the character is good or bad based on the image is added to the electronic component. Weighting storage means for dividing the character into a matrix of a predetermined number of areas for each character type, and storing weighting regarding presence / absence of a character set for each of the divided areas; A character range detecting means for detecting a range of characters; a character cutting means for cutting out each character from the detected character range; a dividing means for dividing the cut out characters into a matrix consisting of the predetermined number of areas; and the weighting. Calculating means for obtaining the degree of coincidence regarding the value of each pixel on the basis of the weighting for each area stored in the storage means, and the degree of coincidence and a predetermined reference value A character inspection apparatus comprising: a determination unit that determines whether a character is good or bad by comparing with. 5. The calculation means binarizes the value of the pixel based on the presence or absence of a character, and counts the value of the degree of coincidence when the value and the weighting match. The character inspection device described in 4. 6. The weighting storage means is set with three types of weights, that is, whether or not a character exists, whether or not a character exists, and whether or not a character exists. 6. The calculation unit does not count the degree of coincidence in a region weighted as being present or absent.
Character inspection device described. 7. An illumination device for illuminating a character area of the electronic component, the illumination device comprising a ring-shaped first illuminator and two parallel linear second illuminators. The character inspection device according to claim 4, 5, or 6.